This research proposal is an investigation of the local control of alveolar bone metabolism using the precisely timed and localized events of premolar tooth eruption in the dog. In this model system eruption of mandibular premolars is dependent upon the presence of the dental follicle, is independent of the tooth or its development and is characterized by a coordinated resorption of alveolar bone above and formation of bone below the space occupied by the tooth. The specific aims of this proposal are to study the cellular and molecular methods by which these metabolic events in alveolar bone are controlled by different regions of the dental follicle. These studies will use microsurgical, biochemical and morphological methods to remove parts of the dental follicle before active eruption begins, to trace cell lineage in follicle and bone and to analyze the components of the extracellular matrix of the dental follicle. The significance of the proposed research lies in potential clinical applications to control alveolar bone metabolism, prevent tooth loss and restore bone mass in the mandible and maxilla.